I use a 10x jewelers microscope and tweezers to get the alignment perfect. The hardest part is actually applying the solder paste there is no room for registration errors. I triple check everything.
As for the reflow profile I raise the temperature gradually, with the thermocouple taped directly to the PCB with kapton tape. I do this manually, not with an automatic controller.
My toaster oven is a convection model with a fan which helps, and I had some trial and error with the rack position.
The part in question is: TPS62180 which is a dual phase step down converter.
Edit: I think you are conflating I've done both high ball count and 0.5mm. Never both at the same time. I've soldered high ball count Xilinx FPGAs at 0.8mm which was relatively easy. Also I stress these are for prototypes. You can do production runs and that is how the company behind 3DRobotics got their start in the early days of quadrotors but its a whole other ball of wax.
As for the reflow profile I raise the temperature gradually, with the thermocouple taped directly to the PCB with kapton tape. I do this manually, not with an automatic controller. My toaster oven is a convection model with a fan which helps, and I had some trial and error with the rack position.
The part in question is: TPS62180 which is a dual phase step down converter.
Edit: I think you are conflating I've done both high ball count and 0.5mm. Never both at the same time. I've soldered high ball count Xilinx FPGAs at 0.8mm which was relatively easy. Also I stress these are for prototypes. You can do production runs and that is how the company behind 3DRobotics got their start in the early days of quadrotors but its a whole other ball of wax.